Crabcrustaceans

Crabcrustaceans is a hypothetical term that could refer to a group of crustaceans exhibiting characteristics commonly associated with crabs, such as a flattened body, a broad carapace, and ten legs, with the first pair often modified into claws. This term is not formally recognized in biological classification. However, if such a category were to exist, it would likely encompass true crabs (Brachyura) and potentially some closely related superfamilies. True crabs are decapods, meaning they have five pairs of legs. Their evolutionary history is marked by a significant widening of the carapace and a tucking of the abdomen beneath the thorax, a defining feature that distinguishes them from other decapod crustaceans like lobsters and shrimp. The diversity within true crabs is vast, with species inhabiting marine, freshwater, and terrestrial environments across the globe. Their ecological roles vary greatly, from scavengers and predators to filter feeders, playing important roles in their respective ecosystems. The defining morphological features are adaptations for their varied lifestyles, whether it be for burrowing in sand, crawling on rocky seabeds, or navigating the intertidal zone.